The present invention is concerned with the treatment of immunological diseases or inflammation, notably such diseases are mediated by cytokines or cyclooxygenases. The principal elements of the immune system are macrophages or antigen-presenting cells, T cells and B cells. The role of other immune cells such as NK cells, basophils, mast cells and dendritic cells are known, but their role in primary immunologic disorders is uncertain. Macrophages are important mediators of both inflammation and provide the necessary “help” for T cell stimulation and proliferation. Most importantly macrophages make IL-1, IL-12 and TNF-α, all of which are potent pro-inflammatory molecules and also provide help for T cells. In addition, activation of macrophages results in the induction of enzymes, such as cyclooxygenase-2 (COX-2) and cyclooxygenase-3 (COX-3), inducible nitric oxide synthase (iNOS) and production of free radicals capable of damaging normal cells. Many factors activate macrophages, including bacterial products, superantigens and interferon gamma (IFN γ). It is believed that phosphotyrosine kinases (PTKs) and other undefined cellular kinases are involved in the activation process.
Cytokines are molecules secreted by the immune cells, large number of chronic and acute conditions have been recognized to be associated with perturbation of the inflammatory responses. A large number of cytokines participate in this response, including IL-1, IL-6, IL-8 and TNF. It appears that the activity of these cytokines in the regulation of inflammation relies at least in part on the activation of an enzyme on the cell-signaling pathway, a member of the MAP known as CSBP and RK. This kinase is activated by dual phosphorylation after stimulation by physiochemical stress, treatment with lipopolysaccharides or with proinflammatory cytokines such as IL-1 and TNF. Therefore, inhibitors of the kinase activity of p38 are useful anti-inflammatory agents.
Cytokines are molecules secreted by the immune cells that are important in mediating immune responses. Cytokine production may lead to the secretion of other cytokines, altered cellular function, cell division or differentiation. Inflammation is the normal response of the body to injury or infection. However, in inflammatory diseases such as rheumatoid arthritis, pathologic inflammatory processes can lead to morbidity and mortality. The cytokine tumor necrosis factor-alpha (TNF-α) plays a central role in the inflammatory response and has been targeted as a point of intervention in inflammatory diseases. TNF-α is a polypeptide hormone released by activated macrophages and other cells. At low concentrations, TNF-α participates in the protective inflammatory response by activating leukocytes and promoting their migration to extravascular sites of inflammation (Moser et al., J Clin Invest, 83, 444-55, 1989). At higher concentrations, TNF-α can act as a potent pyrogen and induce the production of other pro-inflammatory cytokines (Haworth et al., Eur J Immunol, 21, 2575-79, 1991; Brennan et al., Lancet, 2, 244-7, 1989). TNF-α also stimulates the synthesis of acute-phase proteins. In rheumatoid arthritis, a chronic and progressive inflammatory disease affecting about 1% of the adult U.S. population, TNF-α mediates the cytokine cascade that leads to joint damage and destruction (Arend et al., Arthritis Rheum, 38, 151-60, 1995). Inhibitors of TNF-α, including soluble TNF receptors, Etanercept (Goldenberg, Clin Ther, 21, 75-87, 1999 and anti-TNF-α antibody) and Infliximab (Luong et al., Ann Pharmacother, 34, 743-60, 2000), are recently approved by the U.S. FDA for the treatment of rheumatoid arthritis.
Elevated levels of TNF-α have also been implicated in many other disorders and disease conditions, including cachexia, septic shock syndrome, osteoarthritis, inflammatory bowel disease (IBD) such as Crohn's disease and ulcerative colitis etc.
Elevated levels of TNF-α and/or IL-1 over basal levels have been implicated in mediating or exacerbating a number of disease states including rheumatoid arthritis; osteoporosis; multiple myeloma; uveititis; acute and chronic myelogenous leukemia; pancreatic β cell destruction; osteoarthritis; rheumatoid spondylitis; gouty arthritis; inflammatory bowel disease; adult respiratory distress syndrome (ARDS); psoriasis; Crohn's disease; allergic rhinitis; ulcerative colitis; anaphylaxis; contact dermatitis; asthma; muscle degeneration; cachexia; type I and type II diabetes; bone resorption diseases; ischemia reperfusion injury; atherosclerosis; brain trauma; multiple sclerosis; cerebral malaria; sepsis; septic shock; toxic shock syndrome; fever, and myalgias due to infection. HIV-1, HIV-2, HIV-3, cytomegalovirus (CMV), influenza, adenovirus, the herpes viruses (including HSV-1, HSV-2), and herpes zoster are also exacerbated by TNF-α.
It can be seen that inhibitors of TNF-α are potentially useful in the treatment of a wide variety of diseases. Compounds that inhibit TNF-α have been described in several patents.
Cytokines play an important role in the communication between cells of multicellular organisms. Early studies indicate that B cells lineage tend to secrete IL-6 in response to host immune defense mechanisms, but in recent decades studies have indicated elevated levels of IL-6 in various cancer phenotypes.
IL-6 has been found to be a growth factor for multiple myeloma cells; anti IL-6 antibodies were shown to block myeloma cell proliferation in leukemic patients Klein et al., Blood, 78, 5, 1198-1204, 1991 and Lu et al., Eur. J. Immunol., 22. 2819-24, 1992.
Elevation of inflammatory cytokine levels, particularly IL-6 and TNF-α also appears to be associated with the cancer-related cachexia, a syndrome involving loss of adipose and skeletal muscle tissue and one that is not responsive to increased caloric intake. Cachexia may also be related to the role of acute phase proteins. The acute phase response and production of acute phase proteins e.g., C-reactive protein (CRP) are mediated by IL-6. Studies correlate elevated levels of IL-6 to elevated acute phase proteins, which interestingly are also associated with increased weight loss and decreased survival. Thus, with elevated IL-6 levels, amino acid metabolism is directed away from peripheral tissues to the liver for production of acute phase proteins, this in turn leads to muscle wasting, which is a component of cachexia. Accordingly, the cytokine-induced acute phase response may be a primary component of cancer-related cachexia. Moreover, diminishing or blocking IL-6 activity in animal models attenuates cachexia, further demonstrating the essential role IL-6 plays in the development of this syndrome.
Thus, having a compound with IL-6 inhibitory activity may be useful for various inflammatory diseases, sepsis, multiple myeloma, plasmacytoid leukemia, osteoporosis, cachexia, psoriasis, Nephritis, Kaposi's sarcoma, rheumatoid arthritis autoimmune disease, endometriosis and solid cancer (WO02/074298 A1). Compounds that inhibit IL-6 have been described in U.S. Pat. Nos. 6,004,813; 5,527,546 and 5,166,137.
The cytokine IL-1β also participates in the inflammatory response. It stimulates thymocyte proliferation, fibroblast growth factor activity and the release of prostaglandins from synovial cells. Elevated or unregulated levels of the cytokine IL-1β have been associated with a number of inflammatory diseases and other disease states, including but not limited to adult respiratory distress syndrome, allergy, Alzheimer's disease etc. Since overproduction of IL-1β is associated with numerous disease conditions, it is desirable to develop compounds that inhibit the production or activity of IL-1β.
In rheumatoid arthritis models in animals, multiple intra-articular injections of IL-1 have led to an acute and destructive form of arthritis (Chandrasekhar et al., Clinical Immunol Immunopathol. 55, 382, 1990). In studies using cultured rheumatoid synovial cells, IL-1 is a more potent inducer of stromelysin than TNF-α. (Firestein, Am. J. Pathol. 140, 1309, 1992). At sites of local injection, neutrophil, lymphocyte and monocyte emigration has been observed. The emigration is attributed to the induction of chemokines (e.g., IL-8) and the up-regulation of adhesion molecules (Dinarello, Eur. Cytokine Netw. 5, 517-531, 1994).
In rheumatoid arthritis, both IL-1 and TNF-α induce synoviocytes and chondrocytes to produce collagenase and neutral proteases, which leads to tissue destruction within the arthritic joints. In a model of arthritis (collagen-induced arthritis, CIA in rats and mice) intra-articular administration of TNF-α either prior to or after the induction of CIA led to an accelerated onset of arthritis and a more severe course of the disease (Brahn et al., Lymphokine Cytokine Res. 11, 253, 1992; and Cooper, Clin. Exp. Immunol. 898, 244, 1992).
IL-8 has been implicated in exacerbating and/or causing many disease states in which massive neutrophil infiltration into sites of inflammation or injury (e.g., ischemia) is mediated; chemotactic nature of IL-8, including, but is not limited to, the following: asthma, inflammatory bowel disease, psoriasis, adult respiratory distress syndrome, cardiac and renal reperfusion injury, thrombosis and glomerulonephritis. In addition to the chemotaxis effect on neutrophils, IL-8 also has ability to activate neutrophils. Thus, reduction in IL-8 levels may lead to diminish neutrophil infiltration.
IL-12 is a heterodimeric cytokine. Consisting of a p40 and a p35 subunit with potent immunoregulatory properties, primarily released by antigen-presenting cells, dendritic cells and monocytes/macrophages in response to bacterial product and immune signals. It enhances natural killer (NK)-mediated cytotoxicity and induces interferon-gamma (IFN-g) production by NK cells and T lymphocytes. IL-12 plays a key role in promoting Th1 immune responses, as demonstrated both in vitro and in vivo. Accordingly, antibodies against IL-12 have been used to beneficial effect in experimental models for auto immune diseases that are Th1-driven, such as experimental allergic encephalomyelitis (EAE) and 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced chronic intestinal inflammation in mice, a model for human inflammatory bowel disease. In TNBS treated mice, administration of anti-IL-12 after induction of colitis let to a striking improvement of established disease, clinically and histo-pathologically, associated with a decrease in IFN-g production by ex vivo stimulated lamina propria CD4+ cells. Similarly, anti-IL-12 treatment in C3H mice infected with Borrelia burgorferi significantly reduced the severity of Lyme arthritis, accompanied by a decrease in IFN-g serum levels. Several lines of evidence support the critical role of IL-12 in the pathogenesis of CD, including IL-12 expression by mononuclear cells also increased in CD patients versus controls (Kakazu T et al. Am J Gastroenterol. 1999, 94, 2149-2155).
IL-12 production was increased in surgical specimens from CD patients compared with specimens from control patients with cecum cancer (Colpaert S et al. Eur Cytokine Netw. 2002, 13, 431-437). Many clusters of IL-12-positive cells were found in pediatric CD ileal specimens and gastric mucosa, compared with few or no clusters in H. pylori gastritis specimens and normal gastric mucosa (Berrebi D et al. Am J Pathol. 1998, 152, 667-672). Substantial proportions of IL-12-containing macrophages were present in the intestinal lamina propria and muscularis propria in active CD, whereas these cells were rarely detected or were undetectable in controls with non-inflammatory gut disorders (Parronchi P et al. Am. J. Pathol. 1997, 150, 823-832). IL-12 p40 mRNA was detected in lamina propria mononuclear cells isolated from 11/13 patients with CD compared with 1/13 healthy controls (P<0.001) (Monteleone G et al. Gastroenterology. 1997, 112, 1169-1178). IL-12 mRNA expression was significantly increased in colonic biopsy specimens from patients with active CD compared with healthy controls (P<0.04) (Nielsen O H et al. Scand. J. Gastroenterol. 2003, 38, 180-185)
It has been reported that the cyclooxygenase enzyme exists in three isoforms, namely, COX-1, COX-2 and COX-3. COX-1 enzyme is essential and primarily responsible for the regulation of gastric fluids whereas COX-2 enzyme is present at the basal levels and is reported to have a major role in the prostaglandin synthesis for inflammatory response. These prostaglandins are known to cause inflammation in the body; hence, if the synthesis of these prostaglandins is stopped by way of inhibiting COX-2 enzyme, inflammation and its related disorders can be treated. COX-3 possesses glycosylation-dependent cyclooxygenase activity. Comparison of canine COX-3 activity with murine COX-1 and COX-2 demonstrated that this enzyme is selectively inhibited by analgesic/antipyretic drugs such as acetaminophen, phenacetin, antipyrine and dipyrone and is potently inhibited by some nonsteroidal anti-inflammatory drugs. Thus, inhibition of COX-3 could represent a primary central mechanism by which these drugs decrease pain and possibly fever. Earlier reports prior to Coxib's development show that inhibitors of COX-1 enzyme causes gastric ulcers, whereas selective COX-2 and COX-3 enzyme inhibitors are devoid of this function and hence are found to be safe. But, recent reports show that the selective COX-2 inhibitors (COXIB's) are associated with cardiovascular risks. So, inhibition of COX-2 without causing cardiovascular risks and gastric ulcers due to inhibition of COX-1 are shown to be safe.
Phosphodiesterases (“PDE”) are a family of enzymes that metabolise 3′S′ cyclic nucleotides to 5′ nucleoside monophosphates thereby terminating camp second messenger activity. A particular phosphodiesterase, phosphodiesterase-4 (“PDE4” also known as “PDE IV”), which is a high affinity, cAMP specific, type IV PDE, has generated interest as potential target for the development of novel anti-asthmatic and anti-inflammatory compounds. PDE4 is known to exist as at least four isoenzymes, each of which is encoded by a distinct gene. Each of the four known PDE4 gene products is believed to play varying roles in allergic and/or inflammatory responses. Thus it is believed that inhibition of PDE4, particularly the specific PDE4 isoforms that produce detrimental responses, can beneficially affect allergy and inflammation symptoms. It would be desirable to provide a method of treatment of rheumatoid arthritis by administering compounds and compositions that inhibit PDE4 activity.
A major concern with the use of PDE4 inhibitors is the side effect of emesis which has been observed for several candidate compounds as described in the patents U.S. Pat. No. 5,622,977, WO 99/50262, U.S. Pat. Nos. 6,410,563 and 5,712,298. It was also described the wide variation of the severity of the undesirable side effects exhibited by various compounds. There is a great interest and research of therapeutic PDE4 inhibitors as described in the above mentioned patents and references cited therein.